Conventionally, in the production of a semiconductor device, fine processing by the lithography using a photoresist composition has been performed. The fine processing is a processing method including: forming a thin film of a photoresist composition on a substrate to be processed, such as silicon wafer; irradiating an activating light ray, such as an ultra violet ray onto the resultant thin film through a mask pattern in which a pattern of a semiconductor device is depicted to develop a photoresist pattern; and subjecting the substrate to be processed, such as silicon wafer to etching processing using the resultant photoresist pattern as a protecting film. Recently, however, the high integration of semiconductor devices is progressed and the activating light ray adopted tends to have a shorter wavelength, such as from a KrF excimer laser (248 nm) to an ArF excimer laser (193 nm). Following such a tendency, the influence of diffuse reflection of an activating light ray from the substrate or of a standing wave has become a large problem. Thus, a method of providing a reflection preventing film (bottom anti-reflective coating, BARC) between the photoresist and the substrate to be processed is widely studied.
In future, when the miniaturization of the resist pattern progresses, there are caused a problem of the resolution and a problem of the collapse of the resist pattern after the development, so that the thinning of the resist becomes desired. Therefore, it is difficult to obtain a film thickness of the resist pattern sufficient for processing the substrate and a process for imparting a function as a mask during processing the substrate to not only the resist pattern, but also a resist underlayer film produced between a resist and a semiconductor substrate to be processed, has become necessary. At present, as a resist underlayer film for such a process, differently from a conventional resist underlayer film having a high etching rate (having a high etching speed), a resist underlayer film for lithography having a selection ratio of the dry etching rate close to that of a resist, a resist underlayer film for lithography having a selection ratio of the dry etching rate smaller than that of a resist and a resist underlayer film for lithography having a selection ratio of the dry etching rate smaller than that of a semiconductor substrate, have become required (for example, see Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4).
In addition, to such a resist underlayer film, a reflection preventing function can be imparted and then, such a resist underlayer film can have a function of a conventional reflection preventing film in combination with other functions.
On the other hand, for obtaining a fine resist pattern, a process for making a resist pattern and a resist underlayer film during dry-etching a resist underlayer film thinner than a pattern width during a resist development has started to be used. Then, as a resist underlayer film for such a process, differently from a conventional reflection preventing film having a high etching rate, a resist underlayer film having a selection ratio of the dry etching rate close to that of a resist has become required.
In addition, to such a resist underlayer film, a reflection preventing function can be imparted and then, such a resist underlayer film can have a function of a conventional reflection preventing film in combination with other functions.
[Patent Document 1]
Japanese Patent Application Publication No. JP-A-2002-296789
[Patent Document 2]
Japanese Patent Application Publication No. JP-A-2004-177668
[Patent Document 3]
Japanese Patent Application Publication No. JP-A-2004-271838
[Patent Document 4]
Japanese Patent Application Publication No. JP-A-2005-250434